1. Field of the Invention
The present invention relates to a retrieving technique of a file recorded on a recording medium.
2. Description of the Related Art
In recent years, recording media of a large capacity as well as a CD (Compact Disk), a DVD (Digital Versatile Disk), a memory card or the like have been increased and many and many kinds of digital content files (files of image data or music data) have been processed by using these media. Ordinarily, these recording media can be read by various kinds of devices such as a computer, a printer, a television or the like. Accordingly, a technique for improving what is called a compatibility between the devices of the media has been developed so that a movement and an exchange through the recording media can be safely carried out.
MVP (Music Photo Video: a registered trademark of Optical Storage Technology Association) is one of it and this is a systematic standard that makes it possible to read the recording media by various kinds of devices. Further, a technique has been also known that the files are efficiently managed by such a standard to improve a convenience (for instance, see JP-A-2005-327257).
In the above-described related art, an importance is attached to efficiency in view of what is called a management, for instance, to efficiently manage the files and improve a convenience and an importance is not attached to en efficiency in view of a speed such as a reading speed (a speed for retrieving a file) of the recording media.
In the case of the MPV standard, information showing the contents of a file main body recorded on the recording media is recorded in the recording media. This information is called a manifest. This information is used so that it can be instantaneously decided what kind of file main body is recorded on the recording media without recognizing the presence thereof one by one. However, in the manifest, a plurality of file names respectively corresponding to a plurality of file systems can be written in one file main body. Therefore, in order to read the file main body, one file name needs to be specified. When there is a file name corresponding to the file system used during recording it in the recording media, the file name can be used unconditionally to use it as a retrieved result. When such a file name does not exist, the plurality of file names described in the manifest are used to recognize whether or not the file main body can be accessed. In such a collating process of the file main body, much time is required. When the number of files is more increased, the influence thereof is the more increased.